Release 1.3.3

## What's Changed

• restore toplevel re-exports for full 1.2 API compatibility by @ebroecker in #929
• docs: quote pip extras url in installation instructions by @ebroecker in #932
• ci: test python 3.9 in the matrix by @ebroecker in #930
• dbc: import BA_ BU_ attribute for unknown ecu by @ebroecker in #931
• j1939: fill unset bits with 1 on encode by @ebroecker in #933
• fix: fix canmatrix.utils import in xlsx by @umverteiler in #934

New Contributors

• @umverteiler made their first contribution in #934

Full Changelog: 1.3.2...1.3.3